1. Field of the Invention
The invention is directed to a housing for an electromechanical component, particularly for a relay, comprising a housing wall tightly terminating a gas-filled interior, whereby the housing wall forms a severable projection toward the outside into which a channel extends proceeding from the interior.
2. Description of the Related Art
In electromechanical components such as relays, there is often the demand that they must be tight for soldering onto printed circuit boards in order to avoid the penetration of liquid cleaning and soldering agents as well as of vapors. To this end, the housing is usually closed with casting compound at the terminals side, as a result whereof the feed throughs for the terminal pins and the gaps between the base and cap are closed. It has proven expedient, however, to provide such a housing having plastic encapsulation with an aeration opening for further utilization after the soldering in order to prevent the creation of a contactdamaging microclimate in the interior of the housing. This microclimate, for example, is influenced by inadequate heat elimination when switching higher currents.
To this end, it is known from, for example, DE-U-80 17 121 to apply a projection in the form of a hollow cone or cylinder to a housing cap of a relay. This projection is cut off with a tool after the relay is soldered in, as a result whereof the channel extending from the interior of the housing into the projection is opened up. The cross section of the aeration opening is prescribed by the channel cross section at the defined parting location. When, thus, the relay should experience differing aeration for different applications and different switching loads, this must be taken into consideration from the very outset by different housing caps with correspondingly differently shaped projections.
Given components such as relays having a large gas volume in the housing, on the other hand, there is the problem that an over-pressure arises when sealing the housing with warm casting compound and when curing this casting compound, this over-pressure leading either to pores at the seal locations or potentially causing a bulging of the housing cap. In order to avoid this effect, it is likewise already known to provide an aeration hole in the housing for the main sealing process, this being subsequently closed by thermal deformation or by applying a drop of resin in case a complete termination of the housing is desirable for soldering or for later employment as well. Such closable aeration holes that can also be accommodated in a peg were hitherto respectively provided in a different form and independently of the afore-mentioned, hollow housing projections for subsequent aeration.